Add support for custom response headers (#61)

example:
`--headers header=value;header2=value;`

CHANGELOG.md

@@ -1,5 +1,7 @@
-## 4.0.2-wip
+## 4.1.0
 
+- Add "headers" option to add additional response headers.
+  For example: `--headers="header1=value;header2=value;"`
 - Update minimum Dart SDK to `3.0.0`.
 
 ## 4.0.1

README.md

@@ -43,12 +43,13 @@ $ dhttpd --path build/web/  # Serves app at http://localhost:8080
 
 ```console
 $ dhttpd --help
--p, --port=<port>    The port to listen on.
-                     (defaults to "8080")
-    --path=<path>    The path to serve. If not set, the current directory is used.
-    --host=<host>    The hostname to listen on.
-                     (defaults to "localhost")
--h, --help           Displays the help.
+-p, --port=<port>          The port to listen on.
+                           (defaults to "8080")
+    --path=<path>          The path to serve. If not set, the current directory is used.
+    --headers=<headers>    HTTP headers to apply to each response. header=value;header2=value
+    --host=<host>          The hostname to listen on.
+                           (defaults to "localhost")
+-h, --help                 Displays the help.
 ```
 
 [path]: https://dart.dev/tools/pub/cmd/pub-global#running-a-script-from-your-path

bin/dhttpd.dart

@@ -22,8 +22,17 @@ Future<void> main(List<String> args) async {
   await Dhttpd.start(
     path: options.path,
     port: options.port,
+    headers:
+        options.headers != null ? _parseKeyValuePairs(options.headers!) : null,
     address: options.host,
   );
 
   print('Server started on port ${options.port}');
 }
+
+Map<String, String> _parseKeyValuePairs(String str) => <String, String>{
+      for (var match in _regex.allMatches(str))
+        match.group(1)!: match.group(2)!,
+    };
+
+final _regex = RegExp(r'([\w-]+)=([\w-]+)(;|$)');

lib/dhttpd.dart

@@ -33,11 +33,13 @@ class Dhttpd {
     String? path,
     int port = defaultPort,
     Object address = defaultHost,
+    Map<String, String>? headers,
   }) async {
     path ??= Directory.current.path;
 
     final pipeline = const Pipeline()
         .addMiddleware(logRequests())
+        .addMiddleware(_headersMiddleware(headers))
         .addHandler(createStaticHandler(path, defaultDocument: 'index.html'));
 
     final server = await io.serve(pipeline, address, port);
@@ -46,3 +48,15 @@ class Dhttpd {
 
   Future<void> destroy() => _server.close();
 }
+
+Middleware _headersMiddleware(Map<String, String>? headers) =>
+    (Handler innerHandler) => (Request request) async {
+          final response = await innerHandler(request);
+          final responseHeaders = Map<String, String>.from(response.headers);
+          if (headers != null) {
+            for (var entry in headers.entries) {
+              responseHeaders[entry.key] = entry.value;
+            }
+          }
+          return response.change(headers: responseHeaders);
+        };

lib/src/options.dart

@@ -22,6 +22,12 @@ class Options {
           ' If not set, the current directory is used.')
   final String? path;
 
+  @CliOption(
+      valueHelp: 'headers',
+      help:
+          'HTTP headers to apply to each response. header=value;header2=value')
+  final String? headers;
+
   @CliOption(
       defaultsTo: defaultHost,
       valueHelp: 'host',
@@ -34,6 +40,7 @@ class Options {
   Options({
     required this.port,
     this.path,
+    this.headers,
     required this.host,
     required this.help,
   });

pubspec.yaml

@@ -1,5 +1,5 @@
 name: dhttpd
-version: 4.0.2-wip
+version: 4.1.0
 
 description: A static HTTP file server for easy local hosting of a directory.
 repository: https://github.com/kevmoo/dhttpd

test/readme_test.dart

@@ -23,12 +23,13 @@ Future<void> _readmeCheck(List<String> args) async {
 
   expect(expected, r'''```console
 $ dhttpd --help
--p, --port=<port>    The port to listen on.
-                     (defaults to "8080")
-    --path=<path>    The path to serve. If not set, the current directory is used.
-    --host=<host>    The hostname to listen on.
-                     (defaults to "localhost")
--h, --help           Displays the help.
+-p, --port=<port>          The port to listen on.
+                           (defaults to "8080")
+    --path=<path>          The path to serve. If not set, the current directory is used.
+    --headers=<headers>    HTTP headers to apply to each response. header=value;header2=value
+    --host=<host>          The hostname to listen on.
+                           (defaults to "localhost")
+-h, --help                 Displays the help.
 ```''');
 
   expect(readme.readAsStringSync(), contains(expected));